carefully looking at this since my D4 got stolen and I have an empty D4 Seacam housing

Taking Adam´s measures as a guideline to resize images of both cameras (all same length, 160mm, with about 1 mm discrepancy on the height -back view- and width -top view-), I would say that chances to keep access to most of the controls are high with a bit of rerouting and provided your housing has some room (as Seacam does).

Seems like movie rec button would be lost (bigger changes are on top buttons close to the shutter) and front dial wheel might need minor work, together with a slight displacement of buttons on the back